As shown in FIG. 3, a conventional loudspeaker includes voice coil body 2, which is disposed so as it can move freely in magnetic circuit 1 and connected with diaphragm 3 at the inner circumferential end. The outer circumferential end of diaphragm 3 is fixed to frame 5 via edge 4, while the reverse surface of diaphragm 3 is connected to frame 5 via suspension holder 6 and edge 7. Reduction of harmonic distortion and improvement in the linear characteristics of a loudspeaker has been contrived by making use of a symmetric status of edge 4 and edge 7. Japanese Patent Unexamined Publication No. 2004-7332 discloses a loudspeaker of the above-described structure.
In fabricating a loudspeaker of the above structure, diaphragm 3 is set to a position by having the inner circumferential end of diaphragm 3 to make contact with voice coil body 2's outer wall surface, and the two items are glued together in this state. Therefore, a stress due to the mutual contact can not help affecting a deflection state of edge 4 locating at the outer circumference of diaphragm. So, it is difficult to provide an initial symmetry with edge 4 and edge 7. Therefore, suppressing completely the harmonic distortion of a loudspeaker remains as an outstanding problem.